title: Directed epicardial assistance in ischemic cardiomyopathy: flow and function using cardiac magnetic resonance imaging.
abstract: BACKGROUND
  Heart failure after myocardial infarction (MI) is a result of increased myocardial workload, adverse left ventricular (LV) geometric remodeling, and less efficient LV fluid movement. In this study we utilize cardiac magnetic resonance imaging to evaluate ventricular function and flow after placement of a novel directed epicardial assist device.
  
  
  METHODS
  Five swine underwent posterolateral MI and were allowed to remodel for 12 weeks. An inflatable bladder was positioned centrally within the infarct and secured with mesh. The device was connected to an external gas exchange pump, which inflated and deflated in synchrony with the cardiac cycle. Animals then underwent cardiac magnetic resonance imaging during active epicardial assistance and with no assistance.
  
  
  RESULTS
  Active epicardial assistance of the infarct showed immediate improvement in LV function and intraventricular flow. Ejection fraction significantly improved from 26.0% ± 4.9% to 37.3% ± 4.5% (p < 0.01). End-systolic volume (85.5 ± 12.7 mL versus 70.1 ± 11.9 mL, p < 0.01) and stroke volume (28.5 ± 4.4 mL versus 39.9 ± 3.1 mL, p = 0.03) were also improved with assistance. End-diastolic volume and regurgitant fraction did not change with treatment. Regional LV flow improved both qualitatively and quantitatively during assistance. Unassisted infarct regional flow showed highly discoordinate blood movement with very slow egress from the posterolateral wall. Large areas of stagnant flow were also identified. With assistance, posterolateral wall blood velocities improved significantly during both systole (26.4% ± 3.2% versus 12.6% ± 1.2% maximum velocity; p < 0.001) and diastole (54.3% ± 9.3% versus 24.2% ± 2.5% maximum velocity; p < 0.01).
  
  
  CONCLUSIONS
  Directed epicardial assistance can improve LV function and flow in ischemic cardiomyopathy. This novel device may provide a valuable alternative to currently available heart failure therapies.
authors.affiliation: Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-5156, USA.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: McGarvey
authors.forename: Norihiro
authors.initials: N
authors.lastname: Kondo
authors.forename: Manabu
authors.initials: M
authors.lastname: Takebe
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Koomalsingh
authors.forename: Walter R T
authors.initials: WR
authors.lastname: Witschey
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Barker
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takebayashi
authors.forename: Toru
authors.initials: T
authors.lastname: Shimaoka
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Gorman
authors.forename: Robert C
authors.initials: RC
authors.lastname: Gorman
authors.forename: James J
authors.initials: JJ
authors.lastname: Pilla
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D006333:Heart Failure / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery*; D006334:Heart Function Tests / Q000379:methods*; D006353:Heart-Assist Devices; D008279:Magnetic Resonance Imaging; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000503:physiopathology*; D010496:Pericardium; D013552:Swine; D016277:Ventricular Function, Left
keywords: 27; 30; EDV; EF; ESV; ICM; LV; LVOT; MI; ROI; cMRI; cardiac magnetic resonance imaging; ejection fraction; end-diastolic volume; end-systolic volume; ischemic cardiomyopathy; left ventricle; left ventricular outflow tract; myocardial infarction; region of interest